where \(C_{1} \ge C_{2}>0\)  are constants depending only on \(s\)  and \(N\) . These are the generalizations on the results obtained in [1]}, [2]} for \(N=1\) . The same as Lemma 8.2 of [3]}, we know also that the ground state \(U(x)\)  of (REF ) satisfies the following Pohozaev identity:
\(\int _{\mathbb {R}^{N}}|(-\Delta )^{\frac{s}{2}}U|^{2}dx=\frac{N}{N+2s}\int _{\mathbb {R}^{N}}|U|^{\frac{4s}{N}+2}dx.\) 
